EP3877304A1

EP3877304A1 - Apparatus for metering bulk material

Info

Publication number: EP3877304A1
Application number: EP19808989.8A
Authority: EP
Inventors: Robert FELDGES; Jürgen KNEZ
Original assignee: Brabender Technologie & Co KG GmbH
Current assignee: Kubota Brabender Technologie GmbH
Priority date: 2018-11-09
Filing date: 2019-11-05
Publication date: 2021-09-15
Anticipated expiration: 2039-11-05
Also published as: EP3877304C0; WO2020094605A1; EP3877304B1; DE102018128043A1

Abstract

The apparatus for metering bulk material having an inlet in the upper region and having a plurality of conveyor screws (6), wherein the apparatus has bulk material screens (10) above the conveyor screws (6), the conveyor screws (6) are subdivided into different regions, and the different regions of the conveyor screws (6) are covered by the bulk material screens (10), is characterized in that the covered regions are in the form of zones extending transversely to the longitudinal axis of the conveyor screws (6).

Description

Device for dosing bulk goods

The invention relates to a device for dosing bulk goods according to the preamble of claim 1, in particular a dosing device for solids, in

Essentially consisting of a product template and continuous product promotion, namely a material-saving, high-precision powder dosing device for demanding applications e.g. for the pharmaceutical industry, specialty chemicals.

The solid dosing device is primarily for powders, materials as defined under (a). Alternative materials (b) cannot be excluded (hereinafter referred to as "product"):

a. Examples of powder:

o Granules according to the pharmaceutical industry

o dusts

o aerosols

o Nanomaterials

o Poisons, active ingredients, fine chemicals, APIs

b. Other materials (powders, granules according to general chemistry and industry) are not excluded.

The invention is directly related to the following trends in the chemical industries.

(1) Pharmaceutical Industry:

A trend in the industry is the switch from batch / batch production to continuous production. Due to the industry-standard requirements for

Traceability and accuracy require a new dosing technology.

(2) Other industry:

Substances that are of high

Concentration is a danger. ATEX is also an issue in this industry. That is why there are inquiries about dustproof dosing devices in this branch too.

(3) Specialty chemicals / hazardous substances:

With existing dosing technology, occupational safety when processing hazardous substances can often only be guaranteed through the costly insulation of the dosing devices. Dustproof is a requirement in this industry

Dosing devices that do not require isolators (OEB). State of the art

1) Solid dispensers available so far only insufficiently solve the following problems:

a. Dwell time distribution of the product volume in the dosing device b. Mechanical stress on the product in the screw feeders too high, or agglomerate-free dosing not possible

c. Uniform product discharge with low dosing rates

d. Large adjustment range of the dosing capacity

e. Dosing different products with a very different one

Flow properties in a dosing device

Product properties from fluidizing to highly cohesive / generally non-flowable products

f. Dosing device that enables dust-free operation and thus meets the requirements for OEB certification

2) Due to the problems mentioned under (1) there are for various

Applications in specialty chemicals not yet a suitable solid dosing device.

Furthermore, various processes can only be operated with considerable effort, since ATEX zones and MAK values can be achieved without the need for dustproof dosing devices, thanks to complex on-site measures and the appropriate design of components and

Machines must be taken into account. When realizing such systems, it is essential to be able to prevent the atmosphere of an ATEX zone from penetrating into a non-ATEX zone, or with the corresponding technical term, a so-called zone spreading. The consequence would be that e.g. a

flammable atmosphere meets an ignition source.

EP 2 400 059 A2 discloses a method for producing a road surface, a feeder, a paver and a paving train. From this document, the features of the preamble according to claim 1 are known. The road paver contains two screw conveyors and guide plates, which are arranged above the screw conveyors. The baffles, which are called bulk material orifices in the present application, cover the screws in the longitudinal direction and not in the transverse direction. In addition, they do not extend across the entire width of the respective

Auger. A dosing device of an agricultural distributor machine is known from DE 10 2015 118 355 A1. It contains several screw conveyors and also baffles, i.e. bulk material orifices, which, however, do not cover the screw conveyors, but are arranged perpendicular to the longitudinal axis of the screw conveyors and transversely to the conveying direction.

A similar arrangement of screw conveyors and guide plates is known from DE 20 2014 010 804 Ul. Here, too, zones that are not transverse to the longitudinal axis of the screw conveyors are covered by the guide plates.

A discharge unit for bulk material bunkers with several screw conveyors is known from DE 199 12 689 A1. Also from this publication, the arrangement of bulk material orifices with respect to the screw conveyors is not apparent.

DE 35 02 342 A1 is also mentioned, which describes a device for collecting and conveying bulk material. The technical features of claim 1 of the present application also do not emerge from this document.

The state of the art also includes:

EA WAHL US2800252, EA WAHL US3151782, GEA WO2013182869, Hess US3212624, Kardux US4945957, KTron US20070170209A1, Schenck

DE102007055566B4, Schenck DE 102010009753B4, Schenck EP 1220804B1, Schenck EP1401747B1, Schenck EP1954610B1, VibraScrew US5154326, VibraScrew

US5937996.

Object and solution of the invention

Object of the invention: The above-mentioned disadvantages of the prior art are to be avoided.

This object is achieved by the features of claim 1.

It should first be noted that those working with snails

Dosing devices the screws are always filled from behind. According to the invention, a sharper separation of substances to be metered in one after the other (first in, first out) is achieved with the smallest possible mixing area by means of several Screws and the bulk material orifice, because each screw is only filled in a certain zone, i.e. not over the entire length. As a result, the mixing range is significantly smaller than in the prior art.

The following advantages are achieved, inter alia, by the invention:

Advantage a: The dwell time distribution of that in the dosing device

Product volume is reduced.

This advantage is very important. Explanation: Dosing scales discharge continuously and are periodically refilled. An important requirement of quality assurance with which the plant operators are confronted is as follows: The bulk goods added during the periodic filling must not be mixed with the material already in the dosing weigher (principle "first-in-first-out").

This is achieved through:

Conical product template (1) and the asymmetrical outlet (2) (see (la) to (2a) in Figure 1) and the bulk material relief plate (3) and the vibration of this entire structure: vibration drive (s) (7)

The mass flow (section A-A) is made possible by the asymmetrical

Snail trough (4), the bulk material covers (10), the three screw conveyors (6), and the vibration of this entire structure: vibration drive (s) (7)

Advantage b: The mechanical stress on the bulk material is greatly reduced because the activation of the bulk material required for continuous dosing is achieved without using rotating parts that are in direct contact with the bulk material.

This is achieved through:

A very short screw tube (9).

Advantage c: Even product discharge, especially with low

Dosing performance is achieved. In other words: reducing the pulsation This is achieved by:

Mainly through the screw conveyors (6) 3- and 4-speed.

The initial requirement, however, is an even filling of all snails. This is achieved by (identical to advantage a): conical product template (1) and the asymmetrical outlet (2) (see (la) for (2a) in Figure 1) and the bulk material relief plate (3) and the vibration of this entire structure: vibration drive (e) (7)

The mass flow (section A-A) is made possible by the asymmetrical

Screw trough (4), the bulk material covers (10), the three screw conveyors (6), and the vibration of this entire structure (vibration drive (s) (7)). Vibration drives are all available machines that excite vibrations or impulses, e.g.

Magnetic exciters, knockers, ball vibrators, unbalance motors or judge exciters. Advantage d: Large adjustment range of the dosing performance is achieved.

This is achieved by: In the low speed range with up to 4-speed screws and the drive (5). In the high speed range through the vibration drives (7) and the template and

Mass flow (see A). In the prior art, the degree of screw filling decreases too much at high speeds, so that more speed does not cause linearly more bulk material conveyance. Advantage e: The dosing of different products with very different flow properties in one dosing device. Product properties from fluidizing to strongly cohesive / generally non-flowable products.

This is achieved by the same parts as in advantage a.

Furthermore by installing a wide variety of screw types / modular design: three screws, 2 screws, 1 screw, 2-, 3- and 4-flight screws, Concave snails, spiral snails, intermeshing snails,

self-cleaning screws, co-rotating screws, counter-rotating screws.

Advantage f: Dust-free operation is made possible and thus fulfills the requirements for OEB certification.

This is achieved through: Through solid / dust-tight connections between the individual components.

The most important thing is: Low-pulsation dosing for many different types

Applications. Different applications mean:

- different speeds (discharge rates)

- various bulk goods

In second place: first-in-first-out / mass flow / low residence time distribution

When developing the system according to the invention, the inventors have overcome the following technical difficulties in an obvious manner:

• Activation of the bulk goods without:

Rotating parts that cause mixing with the aim: first-in-first-out High energy input into the bulk material with the aim: avoiding bridges, preventing agglomerates

• Low pulsation at low speeds

• Measures which enable the screws to be filled at high speeds. Advantageous refinements of the invention are set out in the subclaims.

Embodiment

An embodiment of the invention is described in more detail below with reference to drawings. In all drawings, the same reference symbols have the same meaning and are therefore only explained once, if appropriate.

Show it

FIG. 1 production direction from right to left, side view,

FIG. 2 sectional view according to FIG. 1 along the line from A to A, view from above, FIG. 3 sectional view according to FIG. 1 along the line from B to B,

Figures 4 to 7, the flow path of the bulk material in the metering device, namely

FIG. 4 sectional view according to FIG. 1 along the line from A to A,

FIG. 5 sectional view according to FIG. 4 along the line from B II to B II,

FIG. 6 sectional view according to FIG. 4 along the line from B III to B III,

FIG. 7 sectional view according to FIG. 4 along the line from B IV to B IV,

FIG. 8 sectional view according to FIG. 2, but with a distance “X” between

Screws 6 and screw tube 9,

Figures 9 to 12 an alternative embodiment according to the invention with internals in the trough on the steep side of the trough, namely

FIG. 9 view according to FIG. 2,

FIG. 10 view according to FIG. 5,

FIG. 11 view according to FIG. 6,

FIG. 12 view according to FIG. 7,

Figures 13 to 14 another alternative embodiment according to the invention, wherein the process part is mirrored, namely

FIG. 13 view according to FIG. 5,

Figure 14 View according to Figure 4 and

FIGS. 15 to 19 further alternative designs according to the invention, with various screw variations, in views according to FIG. 3.

The mass flow here is synonymous with first-in-first-out and synonymous with low residence time distribution.

Fig. 1: The drawing shows a metering device, as it corresponds to the invention with the conical bulk good template (1), which sits on a housing (8) (not absolutely necessary), the drive (5) and the screw tube (9). Other components are covered by the housing (8). The lines from A to A and from B to B define the visual axes of FIGS. 1 and 2.

Fig. 2: Section A to A. In the section you look from above into the feed area of the screw conveyor (6). Through the outlet (2) shown in section, the bulk material flows into the lower part of the invention. The asymmetrical trough (4), supplemented by the built-in screens (10), guides the bulk material in the conveying direction (12), perpendicular to the conveying direction of the screws (11), to the screw conveyors (6). The arrangement of the orifices (10) to the outlet (2) and the geometry of the trough (4), together with the vibration drive (s) (7), significantly influence the degree of filling the screw conveyor (6). The positioning of the components just described to one another is an essential part of the invention and achieves the advantages over the prior art. The screens (10) form with the asymmetrical trough (4) three staggered levels (see also Figures 3, 5, 6, 7), which gradually release the screw conveyors (6) in the direction of production (11) for the bulk material flowing on them. The

Screw conveyors (6) are driven by a drive with one or more gears

Drives (5) set in rotation. The screw conveyors (6) challenge the bulk material through the screw tube (9) out of the dosing device.

Fig. 3: In the conical bulk material template, the bulk material relief plate (3) releases an annular gap for the bulk material. The bulk material unloading plate prevents the bulk material from being compressed and also contributes to the activation of the bulk material and enables the mass flow in the bulk material supply (1). The activation is generated by the vibration drive (7). The resulting movement activates the bulk material (principle: micro-throw / see manual dosing, Gerhard Vetter, publisher: Vulkan Verlag Dec 2001, 2001, ISBN 10: 3802721993 / ISBN 13: 9783802721991).

The exit from the product template (2) is asymmetrical. See Figure 1 and the distance between the axes (la) and (lb). The asymmetry supports the flow of bridge-forming bulk goods and is an important part of the invention.

The easiest way to build a bulk goods product bridge is to use the

opposite supports, on which the bridge ends rest, are symmetrical. Due to the symmetry, almost the bulk of the bulk material on top can be supported on the bottom layer of the bulk material that is at the level of the supports. Due to the symmetry, the almost distributes itself evenly and the bulk material bridge can consolidate. With asymmetrical supports, it is not possible to distribute the almost evenly. As a result, the bulk bridge building up collapses again. The screw conveyors (6) are each 2-course, intermeshing concave screws. In the invention, however, 4- and 3-course intermeshing concave screws (not state of the art) and spiral screws (state of the art) are used. The 4- and 3-course intermeshing concave screws have several bulk material flanks per

Revolution. This can be advantageous at low speeds

Pulsation reduction compared to the prior art can be achieved.

Fig. 4: The drawing defines the planes of the sectional drawings in Figs. 5-7. The principle of mass flow, also known as first-in-first-out or low residence time distribution, is described on the basis of the first sectional drawing in FIG. 5. The mode of operation of the bulk material discharge plate (3) is also described. In the

this area is identical to the following FIGS. 6 and 7.

The area in FIG. 5 to 7 is different in the sectional drawings

asymmetrical snail trough (4). In the area, the bulk material cover (10) partially covers the screws (6). In the production direction (11), the screws (6) are released step by step, so that bulk material (17) from the screws (6) in

Production direction (11) is transported. This detail is an essential part of the invention. Due to the geometry, the number of screws (6) and the orifices, a mass flow is achieved in the area of asymmetrical screw trough (4); see. Line (13) and (14) (principle: progressive conveyor geometries, book: Handbuch Dosieren, second edition, Gerhard Vetter (ed.), Page 102, picture 3.40, ISBN 3-8027-2199-3, 9- 783802-721991) .

Fig. 5: In the conical bulk sample, the bulk level drops during the metering process, in principle, as shown by lines (13) and (14).

The almost parallel course of the two lines (13), (14) is characteristic of the mass flow. Lines (13), (14) are examples of the principle described

Mass flow. According to this principle, the bulk material flows in every point of the dosing device; from the highest to the lowest point, snails (6).

The conical bulk material template is filled with the bulk material (15) in normal metering operation. There is a free volume (16) below the bulk material discharge plate (3).

The bulk material (17) in the area of asymmetrical screw trough (4) reaches all screws (6) in this section.

Fig. 6: Identical to Fig. 5 except for the bulk material (17) in the area of asymmetrical screw trough (4).

A screw (6) is covered in this area by the built-in bulk material cover (10). As a result, the screw (6) is not filled with the bulk material (17) at this point. Fig. 7: Identical to Fig. 5 except for the bulk material (17) in the area of asymmetrical screw trough (4).

The built-in bulk material cover (10) covers two screws (6) in this area. As a result, the screws (6) are not filled with the bulk material (17) at this point.

8 shows a further embodiment. The screw tube is designed differently. The screws are not flush with the pipe, but are withdrawn. This results in a small storage area. The product-specific distance “X” between screws 6 and screw tube 9 results in an advantageous one

Reduction of pulsation.

9 to 12 show an alternative embodiment according to the invention with internals in the trough on the steep side of the trough. The device is therefore built with mirror symmetry, taking into account the function of the individual components.

For example, the panels are not provided on the sloping wall, but on the vertical wall.

13 to 14 show a further alternative embodiment according to the invention, the process part being mirrored. Here too, the device is built with mirror symmetry, taking into account the function of the individual components. Here, e.g. exchanged the vertical wall of the snail trough with the sloping wall.

15 to 19 show further alternative designs according to the invention, here with various screw variations.

The snails are no longer on the imaginary horizontal line, as in Figure 3, with a "line of sight in front of head", but are, for example, arranged in an oblique / tilted line (Fig. 16 to 19) or they are, for example, in one V arranged, in other words, the middle of three screws is offset downwards. Operation of the device for dosing bulk materials

The mode of operation of the device according to the invention is described below

Dosing bulk goods explained in detail:

Step 1: The bulk material gets into the conical bulk material template (1). The bulk material is generally conveyed on the basis of gravity. Manual filling and automated filling are possible.

Step 2: The bulk material is in constant motion, therefore the bulk material is not compressed by the vibration. The vibration is caused by vibration drives (7) and is matched to the direction of flow of the bulk material so that the continuous flow of the bulk material is achieved.

Step 3: In the cone-shaped bulk material template (1), the bulk material flows from the uppermost point of the bulk material volume through an adjustable one

Annular gap, between bulk material template (1) and bulk material relief cone (3) in the direction of the outlet (2). Parts (1), (2) and (3) are asymmetrical. This peculiarity is decisive for the activation of only limited and poorly flowing bulk goods. A mass flow is achieved and thus first-in-first-out is possible (low residence time distribution, see above).

Step 4: Below the conical bulk material feed, in the asymmetrical screw trough (4), the bulk material forms a pouring cone with an angle specific to the bulk material.

Step 5: In the trough (4) and on the bulk material panels (10), the bulk material is fed to the screw conveyors (6) by the vibration.

Step 6: A mass flow is achieved through the circular outlet (2) and the built-in bulk material orifice (10). Mass flow means that in a horizontal section through the bulk material there is an approximately uniform dwell time for everyone

Bulk particles are present.

Step 7: The screw conveyors (6), driven by the drives (5), convey the bulk material from the trough into the screw tube (9). Step 8: The screw conveyors (6) convey the bulk material through the screw tube (9) out of the dosing device.

B e z u g s z e i c h e n l i s t e

1 conical bulk supply

a axis of symmetry of the conical bulk material feed (1)

2 Asymmetrical exit from the product template / asymmetrical to (la) a axis of symmetry of the exit (2)

3 bulk discharge plates

4 Asymmetrical snail trough

5 drive (s)

6 screw conveyors

7 vibration drive (s)

8 housing

9 screw tube

10 bulk solids cover

11 Production direction

12 Direction of conveyance

The other positions are used to show the flow path of the bulk material in the

Dosing device:

13 Level of bulk goods

14 The fill level has dropped due to the dosing process

15 bulk material in the area of conical bulk material template (1)

16 air / free volume below the bulk material relief plate (3)

17 bulk material in the area of asymmetrical screw trough (4)

Claims

Expectations

1. Device for dosing bulk goods with an inlet in the upper

Area and with several screw conveyors (6), the device

Bulk material covers (10) above the screw conveyors (6)

Screw conveyors (6) are divided into different areas and the different areas of the screw conveyors (6) are covered by the bulk material covers (10),

characterized ,

that the covered areas are designed as zones running transversely to the catch axis of the screw conveyors (6).

2. Device for dosing bulk goods according to claim 1,

characterized ,

that the zones extending transversely to the catch axis of the screw conveyor (6) extend over the entire width of the respective screw conveyor (6).

3. Device for dosing bulk goods according to claim 1,

characterized ,

that the front areas of the screw conveyors (6) from the bulk material shutters

(10) not to be covered.

4. Device for dosing bulk goods according to claim 1,

characterized ,

that the bulk material covers (10) diagonally downwards in the direction of the

Screw conveyors (6) are arranged.

5. Device for dosing bulk goods according to claim 1,

characterized ,

that the screw conveyors (6) are arranged horizontally next to one another.

6. Device for dosing bulk goods according to claim 1,

characterized ,

that the screw conveyors (6) interlock.

7. Device for dosing bulk goods according to claim 1,

characterized , that the first screw conveyor is not covered by the bulk material orifices, the rear area of the adjacent second screw conveyor is covered by the bulk material screens and in the case of a third screw conveyor that is adjacent to the second screw conveyor, all areas are covered except for the front area.

8. Device for dosing bulk goods according to claim 1,

characterized ,

that a first, external, screw conveyor is not covered at all by the bulk material orifices (10) and the neighboring screw conveyors are gradually covered more, the covers always encompassing the rear region of the screw conveyors and the most distant from the first screw conveyor (6) Screw conveyor is completely covered except for a front area.

9. Device for dosing bulk goods according to claim 1,

characterized ,

that the device has a bulk material template (1) and

that the outlet (2) of the bulk material feed (1) is arranged in the region of the front ends of the screw conveyors (6).

10. Device for dosing bulk goods according to claim 1,

characterized ,

that the device is designed as a vibrating screw feeder.

11. A device for dosing bulk goods according to claim 1,

characterized ,

that all parts in contact with the product vibrate during operation.

12. Device for dosing bulk goods according to claim 1,

characterized ,

that the conical bulk material feed and / or the bulk material relief plate and / or the screw trough and / or the screw conveyors and / or the screw tube and / or the bulk material orifice vibrate during operation.